U.S. patent number 6,866,931 [Application Number 10/482,416] was granted by the patent office on 2005-03-15 for acrylic based composite fiber and method for production thereof, and fiber composite using the same.
This patent grant is currently assigned to Mitsubishi Rayon Co., Ltd.. Invention is credited to Masanori Akasaka, Masakazu Hoshino, Yukio Kasabou, Ryo Ochi, Eizou Sakurai, Satoru Takeuchi.
United States Patent |
6,866,931 |
Takeuchi , et al. |
March 15, 2005 |
Acrylic based composite fiber and method for production thereof,
and fiber composite using the same
Abstract
An object of this invention is to provide an acrylonitrile based
composite fiber having a new feeling different from that of an
ordinary cellulose acetate fiber, cellulose fiber and acrylic
fiber, excellent spinability, fiber properties and process ability
of yarn spinning, and excellent functions, in particular, a
deodorizing function and a moisture absorbing and retaining
property. The composite fiber is comprised of 10 to 40% by weight
of cellulose acetate and/or cellulose and 60 to 90% by weight of an
acrylonitrile based polymer, and has a structure with the cellulose
acetate and/or cellulose forming an island component in a cross
section perpendicular to a fiber axis and the acrylonitrile based
polymer forming a sea component. Preferably, the cellulose acetate
and/or cellulose as the island component communicate with another
island component in the fiber axis direction, a vacant hole is
provided inside the fiber, or a ratio of the longest diameter and
the shortest diameter of the fiber cross section is 2 or less, and
5 or more recess parts of 0.3 .mu.m or more and 3 .mu.m or less
width and 0.3 .mu.m or more and 3 .mu.m or less depth are provided
in a fiber cross section outer circumferential part. Further
preferably, by applying a heat treatment under alkali in a
production stage, the moisture absorbing and retaining property can
be improved.
Inventors: |
Takeuchi; Satoru (Hiroshima,
JP), Hoshino; Masakazu (Hiroshima, JP),
Ochi; Ryo (Hiroshima, JP), Kasabou; Yukio (Osaka,
JP), Sakurai; Eizou (Aichi, JP), Akasaka;
Masanori (Osaka, JP) |
Assignee: |
Mitsubishi Rayon Co., Ltd.
(Tokyo, JP)
|
Family
ID: |
26618504 |
Appl.
No.: |
10/482,416 |
Filed: |
January 12, 2004 |
PCT
Filed: |
March 19, 2002 |
PCT No.: |
PCT/JP02/02603 |
371(c)(1),(2),(4) Date: |
January 12, 2004 |
PCT
Pub. No.: |
WO03/00867 |
PCT
Pub. Date: |
January 30, 2003 |
Foreign Application Priority Data
|
|
|
|
|
Jul 11, 2001 [JP] |
|
|
2001-210366 |
Mar 14, 2002 [JP] |
|
|
2002-070368 |
|
Current U.S.
Class: |
428/370; 428/373;
428/374; 428/398 |
Current CPC
Class: |
D01F
6/54 (20130101); Y10T 428/2965 (20150115); Y10T
428/2929 (20150115); Y10T 428/2975 (20150115); Y10T
428/2924 (20150115); Y10T 428/2931 (20150115) |
Current International
Class: |
D01F
6/44 (20060101); D01F 6/54 (20060101); D01F
008/00 () |
Field of
Search: |
;428/370,373,374,398 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
2108040 |
|
May 1973 |
|
GB |
|
56-148916 |
|
Nov 1981 |
|
JP |
|
1-259867 |
|
Oct 1989 |
|
JP |
|
2-080611 |
|
Mar 1990 |
|
JP |
|
2-99609 |
|
Apr 1990 |
|
JP |
|
2-154713 |
|
Jun 1990 |
|
JP |
|
3-234808 |
|
Oct 1991 |
|
JP |
|
9-176917 |
|
Jul 1997 |
|
JP |
|
9-291416 |
|
Nov 1997 |
|
JP |
|
10-8327 |
|
Jan 1998 |
|
JP |
|
11-279842 |
|
Oct 1999 |
|
JP |
|
2003089924 |
|
Mar 2003 |
|
JP |
|
Primary Examiner: Edwards; N.
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt, P.C.
Claims
What is claimed is:
1. An acrylic based composite fiber comprising 10 to 40% by weight
of at least one of cellulose acetate or cellulose and 60 to 90% by
weight of an acrylonitrile based polymer, said acrylic based
composite fiber having a structure wherein at least one of the
cellulose acetate or cellulose is present as an island component in
a cross section perpendicular to a fiber axis, and the
acrylonitrile based polymer is present as a sea component, and
single fiber strength is 1.8 CN/dTex or more, dry elongation is 30%
or more, knot strength is 1.8 CN/dTex or more, and knot elongation
is 30% or more.
2. The acrylic based composite fiber according to claim 1, having a
structure wherein at least one of the cellulose acetate or
cellulose is present as the island component and contacts another
island component in a cross section along the fiber axis
direction.
3. The acrylic based composite fiber according to claim 1, wherein
a vacant hole is present inside the fiber.
4. The acrylic based composite fiber according to claim 1, wherein
a ratio of the longest diameter and the shortest diameter of a
fiber cross section is 2 or less, and 5 or more recess parts of
from 0.3 .mu.m to 3 .mu.m width and from 0.3 .mu.m to 3 .mu.m depth
are present in a fiber cross section outer circumferential
part.
5. The acrylic based composite fiber according to claim 1, having a
deodorizing ratio with respect to a carboxylic acid of 90% or
more.
6. The acrylic based composite fiber according to claim 1, having a
deodorizing ratio with respect to an acetic acid of 95% or
more.
7. The acrylic based composite fiber according to claim 1, having a
deodorizing ratio with respect to a nonanal of 90% or more.
8. The acrylic based composite fiber according to claim 1, having a
moisture absorbing ratio Aa at a 40.degree. C. temperature and 90%
RH humidity environment of 15.0% or less, a moisture absorbing
ratio Ab at a 20.degree. C. temperature and 65% RH humidity
environment of more than 2%, and a moisture absorbing ratio
difference .DELTA.A (=Aa-Ab) at the time of transfer from the
40.degree. C. temperature and 90% RH humidity environment to the
20.degree. C. temperature and 65% RH humidity environment of less
than 1.5.
9. The acrylic based composite fiber according to claim 8, wherein
the moisture absorbing ratio Aa at the 40.degree. C. temperature
and 90% RH humidity environment is from 3.0% to 8.0%, and the
moisture absorbing ratio Ab at the 20.degree. C. temperature and
65% RH humidity environment is more than 2% and less than 6.5%.
10. A fiber composite comprising the acrylic based composite fiber
according to claim 1.
11. The acrylic based composite fiber according to claim 2, wherein
a vacant hole is present inside the fiber.
12. The acrylic based composite fiber according to claim 2, wherein
a ratio of the longest diameter and the shortest diameter of a
fiber cross section is 2 or less, and 5 or more recess parts of
from 0.3 .mu.m to 3 .mu.m width from 0.3 .mu.m to 3 .mu.m depth are
present in a fiber cross section outer circumferential part.
13. The acrylic based composite fiber according to claim 2, having
a deodorizing ratio with respect to a carboxylic acid of 90% or
more.
14. The acrylic based composite fiber according to claim 2, having
a deodorizing ratio with respect to an acetic acid of 95% or
more.
15. The acrylic based composite fiber according to claim 2, having
a deodorizing ratio with respect to a nonanal of 90% or more.
16. The acrylic based composite fiber according to claim 2, having
a moisture absorbing ratio Aa at a 40.degree. C. temperature and
90% RH humidity environment of 15.0% or less, a moisture absorbing
ratio Ab at a 20.degree. C. temperature and 65% RH humidity
environment of more than 2%, and a moisture absorbing ratio
difference .DELTA.A (=Aa-Ab) at the time of transfer from the
40.degree. C. temperature and 90% RH humidity environment to the
20.degree. C. temperature and 65% RH humidity environment of less
than 1.5.
17. The acrylic based composite fiber according to claim 16,
wherein the moisture absorbing ratio Aa at the 40.degree. C.
temperature and 90% RH humidity environment is from 3.0% to 8.0%,
and the moisture absorbing ratio Ab at the 20.degree. C.
temperature and 65% RH humidity environment is more than 2% and
less than 6.5%.
18. A fiber composite comprising the acrylic based composite fiber
according to claim 2.
Description
TECHNICAL FIELD
This invention relates to an acrylic based composite fiber
comprising cellulose acetate and/or cellulose, and an acrylonitrile
based polymer, a method for producing the same, and a fiber
composite using the same and another fiber, such as a knitted woven
fabric and a non-woven fabric.
BACKGROUND ART
An acrylic fiber having an excellent color developing property,
bulkiness, heat retaining property and soft feeling is a material
used widely in a clothes field, accessory field, interior field,
material field or the like, and it is developed mainly by staple.
In contrast, cellulose acetate having an excellent glossiness,
color developing property and dry feeling is regarded as a high
quality clothes material, and it is developed mainly by tow and
filament. However, since it does not have a fiber physical property
durable for yarn spinning, it is not developed by staple.
Recently, development of a new material having a new feeling and
functions, such as one having a deodorizing function and a moisture
absorbing and retaining function in particular, is highly demanded,
and as a method for developing techniques, there is polymer
compositing. Complexing of a polymer is an effective method for
reciprocating material characteristics of each other. Several
reports have been provided on the polymer compositing technique of
cellulose acetate and an acrylonitrile based polymer. As to the
feeling, for example, a technique for compositing cellulose acetate
and an acrylonitrile based polymer is disclosed in Japanese Patent
Application Laid-Open (JP-A) Nos. 2-154713, and 3-234808. JP-A No.
2-154713 is for one having a feeling inherent to a conventional
acetate fiber, and JP-A No. 3-234808 is for one having a feeling
inherent to a conventional dry acrylic based fiber.
As to the deodorizing function, for example, JP-A No. 1-259867
discloses a technique for orienting a metal ion to an amide
oximated fiber. However, according to the technique, since the
fiber is colored by a hue inherent to the metal, a ;problem is
involved in that an end use is limited. Furthermore, a technique
for adding a silicate metal salt or an aminomo silicate metal salt
to an acrylic based copolymer (JP-A Nos. 9-176917 and 9-291416) has
been proposed. Since the technique requires a copolymer having
acrylonitrile as a principal constituent unit and a non compatible
polymer having miscibility in addition to an additive, a production
process is complicated. Additionally, although a technique for
containing a titanium oxide having a photo catalyst function in a
fiber (JP-A No. 10-8327) has been proposed, it does not function
effectively at a place whereat ultraviolet rays are weak.
Moreover, as to the moisture absorbing function, which is often
applied by a post-process, washing resistance is poor. Therefore, a
binder such as acrylic resin, an urethane resin and an epoxy resin
is needed for improving durability, which deteriorates the feeling
of the fiber itself, and thus it is problematic. Furthermore, a
technique for compositing a moisture absorbing and discharging
component in a synthetic fiber has been proposed. Although the
technique (JP-A No. 11-279842) has both a moisture absorbing
function and a moisture discharging function, no description is
disclosed for a moisture retaining function thereof.
In order to solve the above-mentioned conventional problems, an
object of the invention is to provide an acrylic based composite
fiber having a new feeling different from that of a conventional
cellulose acetate fiber, cellulose fiber and acrylic fiber,
excellent fiber physical properties and process ability of yarn
spinning, and excellent function properties, in particular, a
deodorizing function and moisture absorbing and retaining
function.
DISCLOSURE OF THE INVENTION
As a result of elaborate discussions by inventors of this invention
for solving the above-mentioned problems, the following invention
has been attained. The object of the invention is an acrylic based
composite fiber composed of 10 to 40% by weight of cellulose
acetate and/or cellulose and 60 to 90% by weight of an
acrylonitrile based polymer, characterized by comprising a
structure with the cellulose acetate and/or cellulose forming an
island component in a cross section perpendicular to a fiber axis
(fiber lateral cross section), and the acrylonitrile based polymer
forming an sea component, a method for producing the same, and a
fiber composite using the above-mentioned composite fiber.
As mentioned above, as a method for developing a new material
having a new feeling, compositing of a polymer is effective. The
inventors surprisingly found out, while promoting discussions for a
polymer compositing technique concerning the cellulose acetate
and/or cellulose and an acrylonitrile based polymer, that the
cellulose acetate and/or cellulose have/has a high deodorizing
function with respect to a carboxylic acid, in particular to an
acetic acid. Accordingly, it was suggested that by using the
cellulose acetate and/or the cellulose as a constituent component
of a fiber product, the deodorizing function can be realized by an
ability of a fiber substrate itself without using a common
deodorizing agent.
Furthermore, it was confirmed that an excellent moisture absorbing
and retaining property, which was not provided in conventional
acrylic based synthetic fibers, was obtained by using the cellulose
acetate and/or cellulose and the acrylonitrile based polymer since
high standard moisture regain of a fiber made of the cellulose,
such as the cellulose acetate and cotton, could be effectively
utilized. Therefore, it was also confirmed that by using the
cellulose acetate and/or the cellulose as a constituent component
of a fiber product, moisture absorbing and retaining performance
could be realized by an ability of a fiber substrate itself without
relying on a post process.
In the invention, cellulose diacetate and cellulose triacetate can
be presented as the cellulose acetate. The cellulose diacetate in
the invention has an average acetylation degree of 48.8% or more
and less than 56.2%, and the cellulose triacetate has an average
acetylation degree of 56.2% or more and less than 62.5%. The
cellulose in the invention may be a polymer containing a cellulose
molecular structure C.sub.6 H.sub.7 O.sub.2 (OH).sub.3, and it may
be a cellulose derivative with a chemical modification added to a
part of a hydroxyl group, such as alkyl cellulose, nitro cellulose,
cellulose xanthate, and ion exchange cellulose as well.
In the invention, the acrylonitrile based polymer is made of
acrylonitrile and an unsaturated monomer polymerizable therewith.
As the unsaturated monomer, an acrylic acid, a methacrylic acid,
alkyl esters thereof, vinyl acetate, acrylic amide, vinyl chloride,
vinylidene chloride, and furthermore, depending on a purpose, an
ionic unsaturated monomer such as sodium vinyl benzene sulfonate,
sodium methacrylic sulfonate, sodium allyl sulfonate, sodium
acrylic amide methyl propane sulfonate, and sodium parasulfophenol
methacrylic ether may be used as well.
According to the composite fiber of the invention, the cellulose
acetate and/or cellulose need to be 10 to 40% by weight, preferably
20 to 30% by weight. In the case where they are less than 10%, a
feeling of a fiber becomes similar to that of the acrylic fiber and
a dry feeling is lost. In addition, as to a deodorizing ratio of a
deodorizing evaluation to be described later, a carboxylic acid is
less than 90% and an acetic acid is less than 95%, and thus a high
deodorizing ability cannot be obtained. In the case where they are
more than 40%, spinability becomes poor, for example fiber breaks
are generated at the time of production, and a fiber property is
lowered, so that a process ability of yarn spinning becomes poor.
Moreover, a soft feeling derived from the acrylic fiber is
lost.
According to the invention, the acrylonitrile based polymer needs
to be 60 to 90%, preferably 70 to 80% by weight. In the case where
it is less than 60% by weight, the spinability becomes poor, and
the fiber physical property is lowered, so that the spinning
process passing property becomes poor. Moreover, the soft feeling
derived form the acrylic fiber is lost. In the case where it is
more than 90% by weight, a feeling of a fiber to be obtained
becomes similar to the feeling of the acrylic fiber so that the dry
feeling is lost.
According to the invention, it is important that, in a fiber cross
section, the cellulose acetate and/or cellulose form an island
component, and the acrylonitrile based polymer forms a sea
component for obtaining the fiber physical property defined in the
invention. By adopting the structure with the cellulose acetate
and/or cellulose being the island component and the acrylonitrile
based polymer being the sea component in the fiber cross section,
circumference of the cellulose acetate and/or cellulose, which have
vulnerable fiber properties, is covered with the acrylonitrile
based polymer, and consequently the fiber is reinforced so as to
obtain the fiber physical property equivalent to the ordinary
acrylic fiber. Moreover, in order to obtain the fiber physical
property equivalent to the ordinary acrylic fiber, a smaller island
size is considered to be advantageous, however, as long as the
fiber physical property defined in the invention is satisfied, the
island size is not at all limited.
It is preferable that the sea island structure in the cross section
in the direction perpendicular to the fiber axis (fiber lateral
cross section) has the cellulose acetate and/or cellulose as the
island component in the cross section in a fiber axis direction
(fiber longitudinal cross section) communicating with another
island component totally or partially for improving the deodorizing
function.
In the invention, a vacant hole denotes a gap formed inside the
fiber. A part of the vacant hole may be opened to a fiber surface,
and moreover, the vacant hole may interlock the islands with each
other. A form and a size of the vacant hole are not limited at all.
Since it is preferable to maintain a fiber strength at 1.8 CN/dTex
or more, those of about less than 2 to 5 .mu.m are preferable
though it depends on the form of the vacant hole. Furthermore,
according to the invention, although a dense structure without a
vacant hole inside the fiber is considered to be advantageous for
maintaining the fiber physical property, existence or absence of
the vacant hole is not at all limited as long as the fiber physical
property defined in the invention is satisfied. In the case of an
application for the purpose of retaining temperature and light
weight, it is rather advantageous to provide the vacant hole.
As to the feeling of the fiber to be obtained, by satisfying a
ratio of the longest diameter and the shortest diameter of the
fiber cross section and a number of recess parts in a fiber cross
section outer circumferential part, dry, tense, and soft feelings
can be provided, which is different from conventional fibers, for
example, cellulose acetate fiber, fibers made of cellulose such as
cotton, rayon, cupra, or the like, and an acrylic fiber. In
addition, it is also effective for the deodorizing.
That is, it is preferable that the ratio of the longest. diameter
and the shortest diameter of the fiber cross section is 2 or less,
and 5 or more recess parts of 0.3 .mu.m or more and 3 .mu.m or less
width and 0.3 .mu.m or more and 3 .mu.m or less depth are provided
in the fiber cross section outer circumferential part for the new
feelings and improving the deodorizing effect. The longest diameter
in the invention is a diameter of a circumscribing circle in
contact with the fiber cross section outer circumferential part,
and the shortest diameter is a diameter of a inscribed circle in
contact with the fiber cross section outer circumferential part.
The recess part in the fiber cross section outer circumferential
part in the invention is a recess part recognizable visually with
an optical microscope, having width and depth of 0.3 .mu.m or more,
which is the lowest limit of a wavelength area of visible
light.
Moreover, the width and the depth of the recess part are 3 .mu.m or
less. If the recess part is in this range, since it is much smaller
than a rain droplet diameter (100 .mu.m to 3,000 .mu.m), and it is
much larger than water vapor (0.00044 .mu.m) ("Special Functional
Fiber" published by CMC, p182, 1983), only the water vapor can pass
through the recess part and the water vapor can easily be diffused
to the outside, and thus the dry feeling tends to be generated.
Furthermore, depending on a number of existing recess parts, color
effect which has not been conventionally provided can be
expected.
Since the ratio of the longest diameter and the shortest diameter
of the fiber cross section is 2 or less, bending rigidity is
increased so as to provide an appropriate tense feeling, and since
5 or more recess parts of 0.3 .mu.m or more and 3 .mu.m or less
width and 0.3 .mu.m or more and 3 .mu.m or less depth are provided
in the fiber cross section outer circumferential part, the dry
feeling is generated, and friction resistance between the fibers is
reduced, so that the soft feeling can be provided. In the case
where the ratio of the longest diameter and the shortest diameter
of the fiber cross section is more than 2, the tense feeling is
lost, and in the case where the recessed parts of 0.3 .mu.m or more
and 3 .mu.m or less width and 0.3 .mu.m or more and 3 .mu.m or less
depth are provided in the fiber cross section outer circumferential
part are provided by less than 5, the dry feeling and the soft
feeling tend to be lost.
According to the invention, single fiber strength is 1.8 CN/dTex or
more, dry elongation is 30% or more, knot strength is 1.8 CN/dTex
or more, and knot elongation is 30% or more. Within these ranges,
in general, process ability of yarn spinning equivalent to that of
ordinary acrylic fiber can be obtained. In the case where the
defined fiber physical properties are not satisfied, that is, if
the single fiber strength is less than 1.8 CN/dTex, the dry
elongation is less than 30%, the knot strength is less than 1.8
CN/dTex, or the knot elongation is less than 30%, the process
ability of yarn spinning becomes poor.
The carboxylic acid in the invention, any one having a carbonyl
group in a molecule, and capable of being present in the air can be
used. Moreover, the carboxylic acid may be any of a monocarboxylic
acid, a dicarboxylic acid, and polycarboxylic acid, and it may be
saturated or unsaturated. Furthermore, a structure having a
functional group other than the carbonyl group may be used as well.
Carboxylic acid species are not particularly limited as long as the
above-mentioned conditions are satisfied. For example, those having
an unpleasant strange odor or stimulus odor in a daily life, such
as a formic acid, an acetic acid, a propionic acid, a lactic acid,
an isolactic acid, a valeric acid, an isovaleric acid, a capronic
acid, a 2-ethyl lactic acid, a capric acid, a 2-ethyl hexanic acid
and an oleic acid, can be presented.
As to adsorption performance, it is important that a adsorption
ratio of the carboxylic acid is 90% or more in the air including
100 ppm or less carboxylic acid by a measurement method to be
described later. Carboxylic acid concentration in the air is set at
100 ppm as a practical evaluation density based on a daily life. In
the case where the carboxylic acid adsorption ratio in the air
including 100 ppm or less carboxylic acid is less than 90%, the
adsorption ability is insufficient. Furthermore, in the case where
the carboxylic acid adsorption ratio in the air including 100 ppm
or less carboxylic acid is less than 90%, tolerant concentration of
the acetic acid as a representative example of the stimulus odor of
the carboxylic acid species, which is 10 ppm, (Principal Chemical
Products 1,000 Kinds Toxicity Data Special Research Report, p19,
Kaigai Gijutsu Shiryo Kenkyusho, 1973) cannot be satisfied.
According to the invention, since the deodorizing ratio with
respect to the acetic acid is 95% or more, the tolerance
concentration can be satisfied sufficiently. In the case where the
deodorizing ratio of the acetic acid is less than 90%, an
adsorption ability tends to be insufficient.
In the invention, the air including the carboxylic acid is not at
all limited as to inclusion of another gas component species as
long as a single or composite carboxylic acid species is/are
provided as a part of constituent components in the air, and the
carboxylic acid is 100 ppm or less. A mechanism of the excellent
deodorizing property of the cellulose acetate and/or cellulose is
not clear yet at the present, however, the inventors assume that a
hydrophilic group of the cellulose acetate and/or cellulose and an
acetyl group of a cellulose acetate side chain are related thereto.
That is, a carboxylic group has a hydrophobic part and a
hydrophilic part in a molecule, and it is assumed that the
hydrophobic part thereof is adsorbed to the acetyl group of the
cellulose acetate side chain, and on the other hand, the
hydrophilic part is adsorbed to the cellulose acetate and/or
cellulose via an affinity with a water molecule so as to realize an
excellent deodorizing ability.
Then, according to the invention, the cellulose acetate and/or
cellulose have/has a particularly high deodorizing ability with
respect to the acetic acid. The reason thereof is presumed that the
acetyl group in the acetic acid and the acetyl group of the
cellulose acetate side chain have stronger affinities. Since the
invention has the deodorizing property for a nonenal as an aldehyde
compound, with a premise that the above-mentioned mechanism is
correct, it is easily presumed that the same deodorizing ability
can be also realized with respect to a substance in the air having
a hydrophobic part and a hydrophilic part in a molecule. In the
case where the deodorizing ratio of the nonanal is less than 90%,
the adsorption ability tends to be insufficient. Preferably, the
deodorizing ratio is 95% and more According to the invention, it is
important that a moisture absorbing ratio Aa under a 40.degree. C.
temperature and 90% RH humidity environment is 15.0% or less, and a
moisture absorbing ratio Ab under the 20.degree. C. temperature and
65% RH humidity environment is more than 2% in terms of appropriate
supply of a moisture absorbing property. That is, as to the
moisture absorbing ratio of the invention, Ab under an average
temperature and humidity environment is more than 2%, and Aa under
a high temperature and high humidity environment is 15.0% or less
equivalent to the standard moisture regain of wool as a natural
fiber ,which is 15%, ("Fiber handbook 2001", edited by Nihon Kagaku
Senni Kyokai, published in December 2000), and thus the moisture
absorbing property with little sticky feeling can be obtained.
Although a desired moisture absorbing property can be obtained by
optionally setting a mixing ratio of the acrylic based composite
fiber according to the invention in a fiber product to be obtained,
preferably the moisture absorbing ratio Aa is 3.0% or more and 8.0%
or less (less than 8.5%, which is the standard moisture regain of
cotton as a representative of a natural fiber). In the case where
it is less than 3.0%, a sufficient moisture absorbing property
tends not to be obtained. Moreover, the moisture absorbing ratio Ab
is preferably more than 2.0% and less than 6.5%. In the case where
Ab is 2.0% or less, the sufficient moisture absorbing property
tends to be hardly obtained. In the case of realizing the moisture
absorbing property of 6.5% or more, content of the cellulose
acetate and/or cellulose needs to be increased, so that the
physical properties such as the fiber strength tend to be
lowered.
According to the invention, it is important that a moisture
absorbing ratio difference .DELTA.A (=Ab-Aa) at the time of
transfer from the temperature 40% and 90% RH humidity environment
to the 20.degree. C. and 65% RH humidity environment is 1.5 or less
in terms of the supply of a moisture retaining property. That is,
it is important that the moisture absorbing ratio difference
.DELTA.A at the time of transfer from the high temperature and
humidity environment to the average temperature and humidity
environment satisfies 1.5 or less in terms of keeping the moisture
retaining property uninfluenced by environment conditions. In the
case where .DELTA.A is more than 1.5, the moisture retaining
property becomes poor. Therefore, since an appropriate moisture
absorbing property and a moisture retaining property are provided
under the different environment conditions in the invention, the
moisture absorbing and retaining properties uninfluenced by the
environment conditions can be obtained. This means that the
moisture retaining property with little sticky feeling can be
obtained stably even in the case of an external environment change
in the summer or winter, or a high temperature and high humidity
environment in clothes immediately after physical exercises.
Furthermore, surprisingly, depending on a ratio of the cellulose
acetate and/or cellulose and the acrylonitrile based polymer, the
acrylic based composite fiber of the invention can obtain the
moisture absorbing ratio of 3.5% or more, which is the standard
moisture regain of a triacetate fiber, or the ratio equivalent to
the standard moisture regain of a diacetate fiber, which is 6.5%,
and of wool, which is 15.0% ("Fiber handbook 2001", edited by Nihon
Kagaku Senni Kyokai, published in December 2000). This means that
in the case where the ratio of the cellulose acetate and/or
cellulose and the acrylonitrile based polymer is same, it tends to
be higher than the moisture absorbing ratio obtained from a mixture
of a fiber of the cellulose acetate and/or the cellulose and a
fiber of the acrylonitrile based polymer (for example, a cloth
using a blended fiber, a knitted or woven product obtained by cross
knitting or cross weaving fibers spun independently, or a pile
product obtained directly by tufting from a sliver without forming
a spun yarn, such as a blanket, or the like). Although a mechanism
is not clear at the present, it is presumed that an increase of
interfaces between the cellulose acetate and/or cellulose and the
acrylonitrile based polymer obtained by the sea island structure is
related.
A fiber composite using the acrylic based composite fiber of the
invention, such as a woven or knitted product and a non-woven
fabric, has a novel feeling, the deodorizing property and the
moisture absorbing and retaining property, which have not been
provided conventionally and it may be a fiber composite including
20% by weight or more of the acrylic based composite fiber of the
invention, preferably 30% or more. Not only being processed in a
spun yarn made of only the acrylic based composite fiber of the
invention, it may be also mixed with a synthetic fiber or a semi
synthetic fiber such as an ordinary acrylic fiber, a polyester
fiber, polyamide fiber and rayon short fiber, and/or cotton, ram
wool, or the like. Moreover, it may be cross knit or cross woven
with a long fiber such as the above-mentioned synthetic fiber or
the semi synthetic fiber and silk. In particular, cloth obtained by
mixing, cross knitting or cross weaving with rayon or ram wool is
provided with a unique feeling, and it is effective in deodorizing
not only an acetic acid odor but also an ammonium odor.
The fiber composite such as the woven or knitted product or the
non-woven fabric using the acrylic composite fiber according to the
invention has a novel feeling and moisture absorbing and retaining
property, which have not been provided conventionally. It may be
provided as a fiber composite including 20% by weight or more of
the acrylic based composite fiber of the invention, preferably 30%
by weight or more, and further preferably 50% by weight or more in
view of obtainment of a mixing homogeneity. Moreover, the fiber
composite using the fiber of the invention is not limited to the
woven or knitted product and the non-woven fabric, and it is
needless to say that it can be also applied to a fiber composite
such as a pile.
As end use of the fiber composite using the acrylic based composite
fiber of the invention, clothing applications such as a sweater, an
inner, a shirt, socks, a jersey, and a skirt, bedding applications
such as a blanket and a sheet, interior applications such as a
carpet, a mat, a chair covering and a curtain, miscellaneous
applications such as toiletry goods, an artificial fur, and a
stuffed animal, and an application for handicraft thread, or the
like can be presented.
The fiber of the invention can be produced for example as follows.
First, an acrylic based composite fiber of the invention comprising
the cellulose acetate and the acrylonitrile based polymer is
obtained, and next, an acrylic based composite fiber of the
invention comprising the cellulose acetate, the cellulose and the
acrylonitrile based polymer is obtained, and furthermore, an
acrylic based composite fiber of the invention comprising the
cellulose and the acrylonitrile based polymer is obtained.
Hereinafter, it will be explained successively.
A spinning solution made of cellulose acetate, an acrylonitrile
based polymer and a solvent is prepared. The solvent is not
particularly limited as long as it is a solvent capable of
dissolving both the cellulose acetate and the acrylonitrile based
polymer. And any of an inorganic acid based one, an inorganic base
aqueous solution based one, and an organic solvent can be used. As
the solvent, for example, a nitric acid (aqueous solution), a zinc
chloride aqueous solution, a rhodanide aqueous solution, dimethyl
formamide, dimethyl acetamide, dimethyl sulfoxide, ethylene
carbonate, propylene carbonate, .gamma.-butylolactone, acetone, or
the like can be presented.
As to a method for preparing the spinning solution, it may be
adjusted by agitating and mixing the cellulose acetate, the
acrylonitrile based polymer and the solvent at the same time at a
room temperature, or by heating or cooling as needed, however, it
is also possible to dissolve the cellulose acetate and the
acrylonitrile based polymer independently in the solvent and mix
them.
In order to obtain the acrylic based composite fiber made of the
cellulose acetate and the acrylonitrile based polymer, having a
fiber structure with the cellulose acetate as the island component
and the acrylonitrile based polymer as the sea component in the
cross section in the direction perpendicular to the fiber axis
according to the invention, a wet spinning method is used, which
provides easy controllability of a coagulation speed of the
spinning solution for forming the recess parts in the fiber cross
section outer circumferential part. Since the coagulation speed by
a dry jet wet spinning method and a dry spinning method other than
the wet spinning method is slow, the recess part formation in the
fiber cross section outer circumferential part becomes
difficult.
The spinning solution is made into a coagulated filament using an
ordinary spinnerette, and it is drawn to 3 to 7 times drawing
ratio. In the case where the drawing ratio is less than 3 times,
mechanical strength of the fiber is lowered, so that spinability
and product durability are lowered. In the case where the drawing
ratio is more than 7 times, process troubles such as+++ a thread
break can be easily generated. An oiling process and a drying
process are applied to a drawn thread by an ordinary method. In
this production method of the invention, functional materials, for
example, a fluorine based compound including a pollution preventive
substance, an amine based compound or natural based substances such
as a chitin and a chitosan having an antibacterial activity, can be
applied to a thread before drying and collapsing processes (a
coagulated thread, a washed thread and a drawn thread).
The composite fiber made of the cellulose acetate and the
acrylonitrile based polymer of the invention accordingly obtained
becomes an acrylonitrile based composite fiber with a totally novel
feeling, which has not been provided in a conventional cellulose
acetate fiber, a cellulose fiber or an acrylic fiber, and an
excellent spinability, fiber physical property, process ability of
the (yarn) spinning, deodorizing property and moisture retaining
property by having the composite ratio, the ratio of the longest
diameter and the shortest diameter in the fiber cross section, the
size and the number of the recess parts in the fiber cross section
outer circumferential part each at a desired value by changing a
mixing ratio of the components cellulose acetate (A) and
acrylonitrile based polymer (B), a ratio of the longest diameter
and the shortest diameter of a spinnerette hole and a coagulation
condition in spinning.
Furthermore, by further processing the composite fiber of the
cellulose acetate and the acrylonitrile based polymer of the
invention obtained as mentioned above by a heating process under
alkali, for example, a process with a sodium hydroxide of 12%
concentration at 60.degree. C. for about 30 minutes with a cotton
dyeing machine, a cheese dyeing machine, a hank dyeing machine, or
the like, the cellulose acetate becomes cellulose, so that the
acrylonitrile based composite fiber made of the cellulose acetate
,the cellulose and the acrylonitrile based polymer of the
invention, having the excellent moisture absorbing property, can be
obtained. Moreover, depending on the concentration of the sodium
hydroxide or the processing condition, the acrylonitrile based
composite fiber made of the cellulose and the acrylonitrile based
polymer of the invention can be obtained. Although an alkaline
agent to be used is not particularly limited, it is preferable to
use a strong alkaline such as the sodium hydroxide.
Moreover, since the moisture absorbing and retaining performance is
improved by the cellulose process, the mixing ratio of the fiber of
invention in an end use product can be lowered, and the mixing
ratio of another functional fiber can be increased. Therefore a
product application for end use can be widened. Furthermore, it is
also effective in terms of widening of the product application for
end use to apply a chemical modification to a part of the hydroxyl
group after the cellulose process so as to have a cellulose
derivative, such as alkyl cellulose, nitro cellulose, cellulose
xanthane, and ion exchange cellulose.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a set of electron microscope photographs of lateral cross
sectional views of each fiber of Examples 1 and 3 according to the
invention and Comparative examples 2 and 4.
FIG. 2 is a set of longitudinal cross sectional views of the
same.
FIG. 3 is a graph showing evaluation results of moisture absorbing
properties of fibers of Example 9 and Comparative example 7.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the invention will be explained further
specifically based on representative examples.
In the examples below, the phrase "% by weight" is indicated simply
as "%".
(Ratio of the Longest Diameter and the Shortest Diameter in a Fiber
Cross Section and a Number of Recess Parts in a Fiber Cross Section
Outer Circumferential Part)
After wrapping a fiber bundle in a paraffin resin, and cutting to a
5 .mu.m thin layer with a microtome, a cut surface was observed
with a transmission type optical microscope (produced by Nikon
Corp., biological microscope E-800), so that a number of the recess
parts of 0.3 .mu.m or more and 3 .mu.m or less width and 0.3 .mu.m
or more and 3 .mu.m or less depth in a fiber cross section outer
circumferential part was counted by visual observation.
(Observation Method for a Sea Island Structure)
After wrapping a fiber bundle in a two-liquid-type urethane resin,
and cutting to 2 mm length with a safety razor, an ion plasma
etching process was applied to a cut surface with a plasma reactor
(produced by Yamato Kagaku Corp., PR-302). After applying metal
sputtering to a processed surface by an ordinary method, it was
observed with a scanning type electron microscope (produced by
Nihon Denshi Corp., JSM-T20).
(Single Fiber Strength, Dry Elongation, Knot Strength and Knot
Elongation)
Methods of 8.7 (tensile strength and a stretching ratio) and 8.8
(knot strength) of JIS L 1015 were used to test a chemical fiber
staple.
(Feeling Evaluation)
Dry, tense and soft feelings were evaluated by a sensory test by
touching with hands.
(Deodorizing Ratio)
As odor components for a deodorizing evaluation, an isovaleric acid
and an acetic acid as representative odors of a carboxylic acid,
and a nonenal (C.sub.6 H.sub.19 O) as an aldehyde compound were
selected.
1 g of a specimen left still under a 20.degree. C. temperature and
65% RH humidity environment for 24 hours was sealed in a 370 mL
triangular flask adjusted so as to have a 50 ppm gas concentration
of the isovaleric acid or the acetic acid. After leaving for 1
hour, the gas concentration in the flask was measured with a
detector tube (Kitagawa type gas detector). For a comparison,
measurement was made in the same manner except that the specimen
was not sealed for obtaining the gas concentration in the flask
after leaving for 1 hour.
A deodorizing ratio was calculated as a ratio of the gas
concentration with the specimen sealed with respect to the gas
concentration of the comparison.
In the case of an ammonium as the odor component of the deodorizing
evaluation, it was evaluated in the same manner except that
ammonium gas concentration was adjusted to 110 ppm in the
above-mentioned evaluation method.
In the case of the nonenal as the odor component of the deodorizing
evaluation, 1 g of a specimen left still under a 20.degree. C.
temperature and 65% RH humidity environment for 24 hours was sealed
in a 125 mL glass Bayer bottle adjusted so as to have a 30 ppm gas
concentration of the nonenal. After leaving for 2 hours, a nonenal
gas concentration was measured with a gas chromatograph. For a
comparison, measurement was made in the same manner except that the
specimen was not sealed for obtaining a relative deodorizing ratio
from a peak area of a gas chromatography.
(Moisture Absorbing Ratio)
After leaving 5 g of a specimen under a 40.degree. C. temperature
and 90% RH humidity environment for 24 hours, it was collected for
measuring a mass and an absolute dry mass thereof. By the following
formula, a moisture absorbing ratio Aa (%) was calculated. In the
same manner, a moisture absorbing ratio Ab of the same evaluation
method except that it is under a 20.degree. C. temperature and a
65% humidity environment was also calculated by the following
formula.
(Cellulose Acetate Weight Reduction Ratio)
After soaking a specimen in an acetone and applying a heat
treatment at 70.degree. C. for 20 minutes, it was washed and dried
absolutely for measuring its weight. In the case where cellulose
acetate is included in the specimen, since the cellulose acetate is
extracted by the acetone, the weight is reduced. However, in the
case where the cellulose acetate is changed into cellulose, weight
change does not take place. The weight change before and after the
acetone extracting process was provided as a cellulose acetate
weight reduction ratio.
Hereinafter, with reference to Examples and Comparative examples of
the invention, characteristics will be compared. "Spinability,
feeling and deodorizing property of Examples 1 to 5 and Comparative
examples 1 to 5"
Spinning solutions were obtained by mixing and dissolving a
cellulose diacetate (A) having a 55.2% average acetylation degree
and an acrylonitrile based polymer (B) (acrylonitrile/vinyl
acetate=93/7 by weight ratio) having a 1.98 reduction viscosity of
a 0.5% dimethyl formamide measurement obtained by aqueous
dispersion polymerization method with solid component ratios shown
in Table 1 in a dimethyl acetamide so as to have a 22% solid
component concentration. The spinning solutions were discharged
into a spinning bath consisting of 56% dimethylacetamide aqueous
solution at 35.degree. C. using a round shape spinarette and drawn
to 6 times while washing with boiling water to prepare drawn
filaments. After that, the filaments were dried and annealed to
prepare fiber with a monofilament fineness of 2.2 dTex.
Evaluation on the fibers with different solid component ratios of
(A)/(B) in terms of spinability, existence or absence of a sea
island structure, a ratio of the longest diameter and the shortest
diameter of a fiber cross section, a number of recess parts of 0.3
.mu.m or more and 3 .mu.m or less width and 0.3 .mu.m or more and 3
.mu.m or less depth generated in a fiber cross section outer
circumferential part, feeling, and a deodorizing property for a
isovaleric acid and an acetic acid, is shown in Table 1. Moreover,
a spinnerette with round shape holes was used except a case of
Example 4 using a spinnerette with elliptical shape holes that has
a 2.0 ratio of a longer axis and a shorter axis. The deodorizing
property with respect to a nonenal was evaluated for a composite
fiber obtained in Example 3 (single fiber fineness 2.2 dTex) and an
acrylic fiber (single fiber fineness 2.2 dTex). Deodorizing ratios
were 95% and 38% respectively. Moreover, moisture absorbing and
retaining property evaluation for fibers used in Examples 1, 3, 5
and Comparative examples 1, 2 is shown in Table 2.
TABLE 1 Ratio of longest (A)/(B) Existence/ diameter Number solid
absence of and of Feeling Deodorizing ratio component sea island
shortest recess Dry Tense Soft Isovaleric Acetic ratio Spinability
structure diameter parts feeling feeling feeling acid acid
Comparative 0/100 Good Absent 2.0 1 Poor Good Good 54 54 example 1
Comparative 5/95 Good Exist 1.5 4 Poor Good Good 73 74 example 2
Example 1 10/90 Good Exist 1.4 5 Slightly Good Good 90 95 good
Example 2 15/85 Good Exist 1.4 6 Good Good Good 91 96 Example 3
30/70 Good Exist 1.3 9 Good Good Good 93 98 Example 4 30/70 Good
Exist 2.0 8 Good Good Good 92 97 Comparative 30/70 Good Exist 2.5
10 Good Poor Good 92 97 example 3 Example 5 40/60 Good Exist 1.2 7
Good Good Good 94 98 Comparative 50/50 Poor -- -- -- -- -- -- -- --
example 4 Comparative 100/0 Good Absent 2.0 5 Good Slightly
Slightly 95 98 example 5 good poor
TABLE 2 (A)/(B) solid Moisture Moisture component absorbing
absorbing ratio ratio Aa (%) ratio Ab (%) .DELTA.A Comparative
0/100 2.4 1.2 1.2 example 1 Comparative 5/95 3.1 1.9 1.2 example 2
Example 1 10/90 4.2 2.8 1.4 Example 3 30/70 6.3 5.0 1.3 Example 5
40/60 7.7 6.3 1.4
FIGS. 1(a) to 1(d) show a lateral cross section of each fiber
obtained by Example 1 and 3, and Comparative examples 2 and 4 by
scanning electron microscope photographs successively. Moreover,
FIGS. 2(a) to 2(d) show a vertical cross section of each fiber
corresponding to the same examples by scanning type electron
photographs successively. These fibers were soaked in an acetone at
70.degree. C. for 30 minutes for extracting cellulose diacetate
components in the fibers, and an ion plasma etching process was
applied thereto for 90 seconds for executing a metal spattering on
processed surfaces thereof.
From these figures, it is understood that a fiber component of the
cellulose diacetate (A) and the acrylonitrile based polymer (B)
constitute a composite fiber having a sea island structure with the
acrylonitrile based polymer (B) providing a sea component and the
cellulose diacetate (A) providing an island component, and the
cellulose diacetate (A) elongates in a fiber direction, partially
communicating with another island component. Furthermore, the
cellulose diacetate (A) component existing on a surface is
extracted into the spinning bath, and it forms recess parts in the
fiber surface according to a difference of coagulation speed
between the cellulose diacetate (A) and the acrylonitrile based
polymer (B).
Therefore, by changing the solid component ratio (A)/(B) of the
cellulose diacetate (A) and the acrylonitrile based polymer (B), a
volume of the cellulose diacetate (A) existing in the acrylonitrile
based polymer (B), and a size and a number of the recess parts in
the surface of the composite fiber can be controlled.
For Example 4 and Comparative examples 1, 3 and 5 in Table 1,
evaluation was executed for the fibers obtained in the same
conditions as those of another examples and the comparative
examples except that a hole shape of the spinnelette was changed
from a round type to an elliptical type to prepare the fiber with a
ratio of the longest diameter and the shortest diameter as shown in
Table 1.
In the case of Comparative example 4 with the (A)/(B) solid
component ratio of 50/50, the fiber cannot be obtained stably
because filament breaks were generated frequently at the spinning
process. Therefore, execution of the evaluation thereof was
impossible as well.
As it is understood from Table 1, even in the case where the ratio
of the longest diameter and the shortest diameter of the composite
fiber is 2, if the number of the recess parts appearing on the
fiber surface is 4 or less, a dry feeling is poor, and deodorizing
performance with respect to the isovaleric acid and the acetic acid
is low.
Moreover, as to a feeling evaluation for a commercially available
cellulose diacetate 100% fiber as Comparative example 5 (produced
by Mitsubishi Rayon Corp. "Linda" 3.3 dTex), although the dry
feeling and the tense feeling were equivalent to those of the
acrylic based composite fiber of the invention, the soft feeling
was poor compared with the acrylic based composite fiber of the
invention.
Process Ability of Yarn Spinning of Examples 1, 3, 5 and
Comparative Example 6
Next, for the composite fibers of the above-mentioned Examples 1,
3, and 5 and Comparative example 6, strength, dry elongation, knot
strength, knot elongation and process ability of yarn spinning of
each single fiber were evaluated. Results are shown in Table 3.
Here, the composite fiber of Comparative example 6 was produced in
the same conditions as the Comparative example 4 except that the
drawing ratio was changed to 3 times.
As to the evaluation of the process ability of yarn spinning, spun
yarn of a 2/32 yarn number count were produced by cutting the
composite fibers of Example 1, 3, and 5 and the new comparative
example 6 having the different (A)/(B) solid component ratios to 51
mm, and mixing with an ordinary acrylic fiber of 2.2 dTex and a 51
mm fiber length at 30/70 mixing ratio.
TABLE 3 Solid com- ponent Process mixing Single Dry Knot ability of
ratio of fiber elon- Knot elon- yarn A/B strength gation strength
gation Spinning Example 1 10/90 2.3 41.5 2.2 41.0 Good Example 3
30/70 2.2 41.0 2.0 38.0 Good Example 5 40/60 1.9 32.5 1.8 31.0 Good
Comparative 50/50 1.3 26.0 1.4 24.5 Poor example 6
As it is apparent from Table 3, there is no problem in the process
ability of yarn spinning for Examples 1 and 3. As to the process
ability of yarn spinning with the (A)/(B) solid component ratio of
40/60 (Example 5), although fly is generated slightly, it was at a
level substantially without a problem. In contrast, in the case of
Comparative example 6 with the (A)/(B) solid component ratio of
50/50, the spinability is poor (for example the filament breaks
were generated frequently at the spinning process). Moreover, the
process ability of yarn spinning was poor. (Fly is generated.)
From this, it was learned that the process ability of yarn spinning
equal to that of an ordinary acrylic fiber spinning process can be
obtained as long as the single fiber strength of the
above-mentioned composite fiber is 1.8 CN/dTex or more, the dry
elongation is 30% or more, the knot strength is 1.8 CN/dTex or more
and the knot elongation is 30% or more. In the case where these
values are not satisfied as in the case of the composite fiber of
Comparative example 6, the process ability of yarn spinning becomes
poor.
"Deodorizing Property of Each Kind of Spun Yarn with Respect to an
Acetic Acid, an Ammonia and a Nonenal"
Knitted fabric of a plain stitch organization was knitted after
cutting the composite fiber obtained in Example 3 (single fiber
fineness 2.2 dTex), the acrylic fiber (single fiber fineness 2.2
dTex), rayon (single fiber fineness 1.3 dTex), and ram wool (64S)
each by 51 mm, and mixing by the mixing ratio shown in Table 4, and
producing spun yarns of a 1/52 yarn number. On the other hand, a
dyeing liquid was prepared by adding 0.25 g of a dye (Hodoya Kagaku
Corp., Kachiron Blue KGLH), 1 g of an acetic acid, and 0.25 g of a
sodium acetate to 1,000 g of pure water. The dyeing liquid was
heated to 100.degree. C. 50 g of the above-mentioned knitted fabric
was soaked in the dyeing liquid and maintained at 100.degree. C.
for 30 minutes. After that, the dyed fabric was washed with water,
dehydrated and dried, and a cation dyeing was executed. The
deodorizing property of these fabrics with respect to an acetic
acid and ammonia were evaluated. Results are shown in Table 4. The
deodorizing property of the knitted fabrics of Example 6 and
Comparative example 7 with respect to a nonenal was evaluated. The
deodorizing ratios were 90% and 38% respectively.
TABLE 4 Mixing ratio Fiber Deodorizing obtained ratio (%) in
Acrylic Acetic Example 3 fiber Rayon Wool acid Ammonia Comparative
0 100 0 0 54 54 example 7 Example 6 30 70 0 0 95 79 Example 7 30 40
30 0 97 94 Example 8 30 40 0 30 96 97
As it is apparent from Table 4, the deodorizing property of the
knitted fabric made of an ordinary acrylic fiber (Comparative
example 7) was not at all satisfactory. In contrast, in the case
that the mixed knitted fabric of the composite fiber of Example 3
and the acrylic fiber, although the deodorizing property of the
fabric has slightly low evaluation in the deodorizing property with
respect to the ammonia, it is no problem in a practical use.
Besides, since it has high deodorizing property evaluation with
respect to the acetic acid, it is easily understandable that the
composite fiber of the invention has the excellent deodorizing
property as well.
"Moisture Absorbing and Retaining Property of Each Kind of Spun
Yarn"
Knitted fabric of a plain stitch organization was knitted after
cutting the composite fiber obtained in Example 3 (single fiber
fineness 2.2 dTex) and the acrylic fiber (single fiber fineness 2.2
dTex) each by 51 mm, and mixing them by a 50/50 mixing ratio, and
producing spun yarns of a 1/52 yarn number. Thereafter, a knitted
fabric with the above-mentioned cation dyeing was obtained (Example
9). After leaving the knitted fabric and a knitted fabric made of
an ordinary acrylic fiber (Comparative example 7) in a 20.degree.
C. temperature and 65% RH humidity environment for 4 hours, they
were left in a 40.degree. C. temperature and 90% Rh humidity
environment for 24 hours and successively left in a 20.degree. C.
temperature and 65% RH humidity environment for 24 hours, then, the
moisture absorbing and retaining property of each knitted fabric
was evaluated. Results are shown in FIG. 3.
Example 9 was superior to the acrylic fiber knitted fabric
(Comparative example 7), and it has a sufficient moisture absorbing
and retaining property in the different environment conditions. The
moisture absorbing property was evaluated for a mixed spun yarn of
a tow of the cellulose diacetate (single fiber fineness 2.2 dTex)
and a tow of the acrylic fiber (single fiber fineness 2.2 dTex) at
15/85 ratio, paralleled by a sliver after leaving it in a
20.degree. C. temperature and 65% RH humidity environment for 24
hours. The moisture absorbing property was 1.8%, which is poorer
than that of Example 9.
Moisture Absorbing Property of Examples 10 to 11 and Comparative
Examples 8 to 10
To prepare samples of Examples 10 and 11, the fibers obtained in
Examples 3 and 4 were treated with different concentration of NaOH
respectively for 30 minutes at 60.degree. C. In the case of
Comparative examples 8 and 9, the fiber obtained in Comparative
example 1 was treated with different concentration of NaOH for 30
minutes at 60.degree.. In the case of Comparative example 10, the
fiber obtained in Comparative example 2 was treated with NaOH which
using amount is 12wt % per fiber weight under the same temperature.
Evaluation on the moisture absorbing property, the weight reduction
ratio of the obtained fibers is shown in Table 5. In the acrylic
based composite fibers of Examples 10 and 11, the cellulose
acetate, the cellulose and the acrylic based polymer were present.
Although the cellulose acetate, the cellulose and the acrylonitrile
based polymer were similarly present in the acrylic based composite
fiber in Comparative example 10, satisfactory performance was not
obtained because the cellulose diacetate is 5%.
Moisture Absorbing Property of Example 12
To prepare the sample of Example 12, the fiber obtained in Examples
5 was treated with NaOH of which using amount is 14wt % per fiber
weight for 30 minutes at 80.degree. C. The cellulose acetate was
changed to be the cellulose by an alkaline process so that the
cellulose and the acrylonitrile based polymer were present in the
acrylic based composite fiber. Evaluation on the moisture absorbing
property and the weight reduction ratio of the obtained fiber is
shown in Table 5.
TABLE 5 Solid Using amount of Cellulose Specimen No. component NaOH
(% with Moisture Moisture acetate weight supplied for mixing ratio
respect to absorbing absorbing reduction NaOH use of A/B fiber
weight) ratio Aa (%) ratio Ab (%) .DELTA.A ratio (%) Example 10
Example 3 30/70 12 8.1 6.8 1.2 30 Example 11 Example 3 30/70 3 4.8
3.2 1.2 11 Example 12 Example 5 40/60 14 13.0 11.6 1.4 40
Comparative Comparative 0/100 3 1.5 1.2 0.3 0 example 8 example 1
Comparative Comparative 0/100 0 1.5 1.2 0.3 0 example 9 example 1
Comparative Comparative 5/95 12 2.5 1.8 0.7 30 example 10 example
2
* * * * *